Invisible water

At this spot the Aiguillon River has carved out a basin in which water remains. You can’t see it but the photo gives evidence that it is there: I notice certain elements and shadows with their reflected mirror images underneath. But I cannot find up to where the water reaches on the basin wall. The branches and shadows don’t make it any easier. I just can’t detect the surface of the water. It is so still and clear that it is invisible. A true miracle.